Monday March 25, 2019
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Habitability Of Surrounding Planets Affected By Super Flares Of Red Dwarfs: NASA

Red dwarfs -- especially young red dwarfs -- are active stars, producing flares blast out energy

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US shutdown delays space missions but NASA not grounded: Report,

Using NASA’s Hubble Space Telescope, astronomers have found that violent outbursts, or superflares, from red dwarf stars could affect the habitability of any planets orbiting it.

Young low-mass stars flare much more frequently and more energetically than old stars and middle-age stars like our Sun, the findings of the study published in the Astrophysical Journal showed.

The findings are based on observations of the flare frequency of 12 red dwarfs.

Hubble is observing such stars through a large programme called HAZMAT — Habitable Zones and M dwarf Activity across Time.

“M dwarf” is the astronomical term for a red dwarf star — the smallest, most abundant and longest-living type of star in our galaxy.

Hubble Telescope. red dwarf
Hubble Telescope. Flickr

The HAZMAT programme is an ultraviolet survey of red dwarfs at three different ages — young, intermediate, and old.

“The goal of the HAZMAT programme is to help understand the habitability of planets around low-mass stars,” explained the programme’s principal investigator, Evgenya Shkolnik from Arizona State University.

“These low-mass stars are critically important in understanding planetary atmospheres,” Shkolnik added.

Stellar flares from red dwarfs are particularly bright in ultraviolet wavelengths, compared with Sun-like stars.

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Artist’s view of planets transiting red dwarf star in TRAPPIST-1 system. Flickr

Hubble’s ultraviolet sensitivity makes the telescope very valuable for observing these flares.

The flares are believed to be powered by intense magnetic fields that get tangled by the roiling motions of the stellar atmosphere.

When the tangling gets too intense, the fields break and reconnect, unleashing tremendous amounts of energy.

The team found that the flares from the youngest red dwarfs they surveyed — just about 40 million years old — are 100 to 1,000 times more energetic than when the stars are older.

This younger age is when terrestrial planets are forming around their stars.

Red dwarf
This illustration shows a red dwarf star orbited by a hypothetical exoplanet. NASA

About three-quarters of the stars in our Milky Way galaxy are red dwarfs. Most of the galaxy’s “habitable-zone” planets — planets orbiting their stars at a distance where temperatures are moderate enough for liquid water to exist on their surface — orbit red dwarfs.

In fact, the nearest star to our Sun, a red dwarf named Proxima Centauri, has an Earth-size planet in its habitable zone.

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However, red dwarfs — especially young red dwarfs — are active stars, producing flares that could blast out so much energy that it disrupts and possibly strips off the atmospheres of these fledgling planets. (IANS)

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NASA Astronauts Spacewalk to Change ISS Batteries

Spacewalkers have now spent a total of 55 days, 21 hours and 39 minutes working outside the station

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NASA researchers have created the atmosphere of a super-hot planet outside our solar system, here on Earth. Pixabay

Two NASA astronauts – Nick Hague and Anne McClain – have successfully completed an over six hour spacewalk and replaced the ageing batteries on the International Space Station (ISS).

During the six hour, 39 minute spacewalk, Hague and McClain replaced nickel-hydrogen batteries with newer, more powerful lithium-ion batteries for the power channel on one pair of the station’s solar arrays, NASA said in a statement on Friday.

They also installed adapter plates and hooked up electrical connections for three of the six new lithium-ion batteries installed on the station’s starboard truss.

These new batteries provide an improved power capacity for operations with a lighter mass and a smaller volume than the nickel-hydrogen batteries.

The batteries store power generated by the station’s solar arrays to provide power to the station when the station is not in the sunlight, as it orbits the Earth during orbital night.

In addition, the astronaut duo also removed debris from outside of the station, securing a tieback for restraints on the Solar Array Blanket Box, NASA said.

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NASA will also have its first all-female spacewalk at the end of the month, when astronauts Anne McClain and Christina Koch will get to float around in space. The spacewalk will last about seven hours, according to the US space agency. Pixabay

McClain will again take a spacewalk on March 29 along with flight engineer Christina Koch to work on a second set of battery replacements on a different power channel in the same area of the ISS.

This would be the first-ever spacewalk with all-female spacewalkers, NASA said.

A third spacewalk on April 8 by Hague and David Saint-Jacques of the Canadian Space Agency will lay out jumper cables between the Unity module and the S0 truss, at the midpoint of the ISS’s backbone.

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This work will establish a redundant path of power to the Canadian-built robotic arm, known as Canadarm2. They will also install cables to provide for more expansive wireless communications coverage outside the orbital complex, as well as for enhanced hardwired computer network capability.

Space station crew members have until now conducted 214 spacewalks in support of assembly and maintenance of the orbiting laboratory.

Spacewalkers have now spent a total of 55 days, 21 hours and 39 minutes working outside the station. (IANS)